Apparatus for controlling twisted yarn



Dec. 20, 1960 S- J. HOEKSTRA APPARATUS FOR CONTROLLING TWISTED YARNFiled Dec. 17. 1956 $705M JACOB FIG. I

FIG. 2

INVENTOR.

HOEKSTRA United States Patent APPARATUS FOR CONTROLLING TWISTED YARNSjoerd Jacob Hoelrstra, Emmen, Netherlands, assignor to American EnkaCorporation, Enka, N.C., a corporation of Delaware Filed Dec. 17, 1956,Ser. No. 628,901

Claims priority, application Netherlands Jan. 5, 1956 1 Claim. (Cl.242-128) This invention relates to an apparatus for controlling twistedyarn. More particularly, this invention relates to an apparatus forcontrolling highly twisted yarn during delivery from a yarn package to aknitting machine.

In the production of certain fabrics having stretchable characteristics,highly twisted yarns are required. Fabrics having unusually highstretching properties may be produced from filaments of certainfiber-forming synthetic thermoplastic polymers which are heat-set in atwisted condition.

A method of producing a heat-set twisted yarn generally comprisestwisting a thermoplastic yarn, multi-filament or monofilament, toprovide either an S-twist or Z-twist, heating the twisted yarn to atemperature suflicient to set the yarn, and cooling the yarn while inthe twisted condition. This is known in the art as a heat-settingoperation. Although this twisted yarn does not lose its twisted shapewhen in a relaxed state, there is a tendency for the yarn to snarl intokinks.

Most any highly twisted yarn presents problems to the knitter. One ofthe greatest problems is the tendency of the yarn to kink between theyarn tensioning devices and the yarn package when the yarn is notcontinuously being fed into the knitting machine. In a knittingoperation, when delivery of a twisted yarn over an end of a package tothe machine is discontinued, the yarn tends to recoil and to twistitself into kinks near the yarn package. When knitting is resumed, thekinks may not be straightened out, with knots resulting. Accordingly, aninferior fabric will be knitted.

One of the most important commercial utilizations of heat-set twistedmonofilament yarn is found in the production of ladies full-fashionstretchable hose. Nylon is the usual material used in the manufacture ofthis type of hosiery. Before being heat-set, the nylon yarn is twistedto 50 or more turns per inch, preferably about 35 turns per inch. Thetemperature required for the heatset step is dependent on the type ofnylon used. For example, nylon yarn produced from the polycondensationof hexamethylene diamine and adipic acid must be heatset at a highertemperature as compared to polycaprolactam nylon yarn.

In the manufacture of certain stretchable fabrics, two strands ofZ-twisted yarn, for example in making womens hose, are knittedalternating successively with two strands of S-twisted yarn. Therefore,while the yarn of one type of twist is being knitted, the yarn of theother type of twist is not moving. Hence, each time the movement of theyarn stops, the kinking problem arises.

Means have been suggested for overcoming the kinking problem. Forexample, caps of various sizes and shapes for yarn packages have beenused. These caps or discs are arranged coaxially with the yarn package.Here, the twisted threads are directed upwardly or downwardly, as thecase may be, from the package and contact the periphery of the discduring the draw-ofi of the yarn. These discs which have not beenentirely satisfactory are constructed from plastic material or the likeand have a smooth or slotted outer edge. When these known discs areemployed in drawing 01f a twisted yarn, the kinking problem is notentirely eliminated.

Although the known types of discs may overcome the kinking problem to alimited extent when the diameter of the discs is about twice the size ofthe diameter of the empty spool, pirn or cone, they are notably lesseffective when the diameter of the yarn package is greater than threequarters of the diameter of the disc.

An object of the present invention is to provide a novel apparatus fordirecting a highly twisted yarn in a discontinuous manner to a knittingmachine without the yarn forming knots or kinks.

Another object of the present invention is to provide a unilaterallyoperating yarn tension device for the prevention of kinking during theidle portion of intermittent unwinding of highly twisted yarn over anend of a yarn holder.

These and other objects will become apparent from the following morecomplete description of the instant invention.

According to the present invention, a yarn holder disc is provided whichovercomes the aforesaid kinking problem. The disc is mounted at one endof a yarn holder containing a package of highly twisted yarn. A strip offur is attached around the periphery of the disc, the hairs of said forprojecting into the path of the yarn and extending outwardly from saiddisc in the direction of rotation of the yarn around said disc duringunwinding. Upon withdrawal of the yarn around the disc in the directionwhich the hairs extend, the yarn will glide over the fur;

but upon discontinuation of withdrawal, the yarn, having a tendency toreverse its direction, becomes tensioned by the hairs and is thusprevented from kinking.

Referring to the accompanying drawing which illustrates one embodimentof the invention;

Figure 1 is a perspective view of a yarn holder disc mounted at an endof and coaxially arranged with a spool on which twisted yarn is wound;and

Figure 2 shows the disc, spool and yarn in a longitudinal sectionalview.

A main feature of the invention consists in the use of the discindicated generally by 11 which comprises a flat sheet-shaped ring 12provided with a raised edge or axially extending flange 13 near itsouter periphery. Reference number 14 denotes an outer radiallyprotruding rim formed beyond the raised edge 13. A strip of fur 15 isattached to the outer side of the edge 13. Rim 14 is sufiiciently narrowthat the hairs of the strip of fur 15 protrude only slightly beyond theedge of the rim.

The inner portion of the ring 12 extending inwardly forms a flange 16which is provided with a plurality of indentations 17. This arrangementprovides a ready means for a force-fit attachment Within the bodyportion 18 of a yarn holder on which yarn 19 is wound.

A thread guide 21 is positioned above the disc 11 so that the thread 20maintains contact with the disc during withdrawal of the thread from theyarn package, for example, by driven roller 22, to a point of use, notshown. Withdrawing endwise from the package of course results inrotating or revolving the yarn about or relative to the package holder.

In Figure 1 the thread 20 has an S-twist and is drawn off in acounterclockwise direction. In order to prevent the formation of kinksin the thread 20, the hairs of the fur piece must also be directedcounterclockwise. Hence, the thread 20 when drawn off will glide overthe hairs, or with the grain.

When the movement of the thread 20 is halted, the thread will tend torecoil in the direction against the grain of fur because of the hightwist contained therein and will immediately be tensioned between thehairs of the fur and thereby be prevented from kinking.

On the other hand, a Z-twisted yarn is run off in a clockwise direction;and in this case a strip of fur will be used in which the hairsof thefur are laid clockwise. The position of the hairs depends upon thedirection in which the yarn is run off which in turn is dependent uponwhether S-twisted yarn or Z-twisted yarn is withdrawn from the yarnpackage. The grain of the hair must run in the direction in which theyarn is removed.

The radially protruding rim 14 prevents the yarn from being pressed toofirmly against the fur 15. Preferably, the edge of rim 14 should notprotrude beyond the outer diameter of the strip of fur. Also, rims maybe arranged at the top and bottom of the strip of fur, if desired,provided neither of said rims has a diameter larger than that of thestrip of fur.

An important feature of the present invention is that the diameter ofthe disc 11 need not substantially exceed the diameter of a fully woundyarn package. This is an advantage since conventional package sizes maybe used without the need of larger humidification chambers onconventional knitting machines.

Furthermore, the diameter of disc 11 with regard to the diameter of theyarn holder is less critical as compared with known discs.

The disc may be an integral part of the body portion of a yarn holder,such as a spool, pirn or bobbin on which the yarn is wound or it may bea force-fit arrangement as shown in Figure 2.

The fur as used in the present invention may be animal fur. Preferablythe fur used in accordance with the present invention should beshort-haired or shorn. Animal fur of various kinds, such as rabbit,squirrel, fox, wolf, and the like, are satisfactory. Of course, fur madefrom synthetic fibers or a blend of natural and synthetic fibers havingphysical characteristics of animal fur is also satisfactory.

The fur may be attached to the disc in any satisfactory way, such as bymeans of glue or other adhesive.

It will be understood, however, that the yarn holder cap may be modifiedwithout departing from the present invention. Thus, the cap may bemanufactured from wood, metal or synthetic material.

What is claimed is:

A unilateral yarn tensioning device operative to prevent kinking duringthe idle portion only of intermittent unwinding comprising an elongatedyarn holder containing a package of highly twisted yarn, a disc mountedat one end of said elongated yarn holder in coaxial relationshiptherewith and having an overall diameter which only slightly exceeds theinitial diameter of the yarn package on said yarn holder, said discincluding a flat ring extending radially of said yarn holder, a rimprotruding radially outwardly from the periphery of said ring, a raisedflange extending axially from said ring near the periphery thereof, anda strip of fur attached around the outer peripheral surface of saidflange, said fur having hairs secured at one end to said flange with thefree ends thereof projecting outwardly of said flange slightly beyondthe outer surface of said rim and extending substantiallycircumferentially about said ring, substantially all of said hairsextending in ,I the same circumferential direction, and means forwithdrawing said highly twisted yarn over the end of said ReferencesCited in the file of this patent UNITED STATES PATENT S 1,206,870 LippsDec. 5, 1916 1,209,179 Lipps Dec. 19, 1916 1,289,987 West Dec. 31, 19181,851,243 Egli Mar. 29, 1932 2,771,756 Burleson et al. Nov. 27, 1956

